Sorry Scott, I have to disagree:
- The extra foot or so of wire weight is trivial.
Get out your tape measure. The typical cable path from the battery/firewall area to the starter motor requires somewhere between 3-4 feet of cable (and the weight per foot of 2 gauge copper wire is not trivial), plus the biggest cabling pain in the engine compartment is properly anchoring wires / cables to the engine around the top of the engine sump. Running a ground cable all the way to the front doubles that.
- Old school ground straps run from the firewall to a greasy engine bolt are not weight free, but do create the potential for future maintenance issues. We need not perpetuate 1960 Cessna thought.
I don't think the starter area of a typical Lycoming is any cleaner than the aft rear of the engine case.
- Odds are that a plane that has a reluctant starter but a charged battery, the problem is a poor ground return from the starter.
I agree, but that problem can exist with any high power cable connection.... regardless of whether it is attached at the engine case or directly on the starter motor. With four bolts mounting the starter, I have never seen a ground problem at that location.